Field
The present disclosure relates generally to communication systems, and more particularly, to enabling distributed frequency synchronization based on a fastest node clock rate as part of device to device (D2D) communications in a wireless wide area network (WWAN).
Background
Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.
These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example of a telecommunication standard is Long Term Evolution (LTE). LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by Third Generation Partnership Project (3GPP). LTE is designed to better support mobile broadband Internet access by improving spectral efficiency, lower costs, improve services, make use of new spectrum, and better integrate with other open standards using OFDMA on the downlink (DL), SC-FDMA on the uplink (UL), and multiple-input multiple-output (MIMO) antenna technology. LTE may support direct device-to-device (peer-to-peer) communication (e.g., LTE-Direct).
Currently, an aspect of supporting device to device (D2D) communications in an LTE environment (e.g., LTE-Direct) is D2D synchronization. D2D synchronization may include timing synchronization and frequency synchronization. Where a D2D communications are supported without a centralized controlling entity, D2D synchronization may be performed in a distributed manner (e.g., amount devices in the network). Distributed frequency synchronization is needed to enable a communication system which works without an infra-structure (e.g., no central controlling entity).
As the demand for device-to-device communication increases, there exists a need for methods/apparatuses for enabling distributed frequency synchronization for supporting D2D communication within LTE.